Perhaps you should try some spelling variations:
quang luan » quang tuan, quang uan, quang xuan
hieu suat » hieu luat, hieu qua
minh quan » minh quang, minh tuan, manh quan
tien soan » bien soan, tien hoang, thien toan
van hieu » cao hieu
quan lan » quan lang, quan van, quan lap
van tien » toan tien, van tuan
lan van » luan van, lang van, tan van

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( dinh ((quang luan) OR (quan luan)) van hieu suat ) or ( minh quan lan van tien soan ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( dinh ((quang luan) OR (quan luan)) van hieu suat ) OR ( minh quan lan van tien soan )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( dinh ((quang luan) OR (quan luan)) van hieu suat ) or ( minh quan lan van tien soan ))".
• Adding a wildcard symbol may retrieve word variants: (( dinh ((quang luan) OR (quan luan)) van hieu suat ) or ( minh quan lan van tien soan ))*.